The present invention relates to a method of making electrical connections between cells within a battery and in particular to an improved method of welding a bus bar between cells in a battery.
Batteries are commonly comprised of one or more electrochemical cells. One known method of making electrical connections between cells in a battery is by using a bus bar. Terminals of the individual battery cells are connected by a bus bar to form a battery. It is advantageous to arrange the terminals so that they may be efficiently and readily connected by the bus bar. For example, the terminals may be arranged in a row so that a straight bus bar makes electrical contact with all of them.
The bus bar is commonly welded to the face of the terminals to achieve effective electrical transmission. Often differences in alignment between the faces of adjoining terminals result in too great of a gap between the terminal face and the bus bar for proper welding. This misalignment may be due to variations in manufacturing of the individual cells.
To assure that the maximum gap allowed by the chosen welding technique is not exceeded, the bus bar is forcibly deformed towards the terminals until the acceptable gap between each terminal and the bus bar is achieved. The bus bar is positioned across the terminals, temporarily held with a tool while the deformation force is applied, and then welded to the terminals. The properties of the bus bar desirable for electrical transmission (for example, material type and mass) may increase the amount of force required for deformation.